Question

Why must you centrifuge the donor strain, discard the media it was originally grown in, and resuspend it in fresh luria broth prior to mixing it with the recipient strain?

-The donor strain produces a lot of acid by fermentation and the low pH would inhibit the growth of the recipient strain.
-The donor strain is grown in media containing the antibiotic kanamycin which would inhibit the growth of the recipient if not removed.
-The donor strain produces a lot of alcohol by fermentation which would inhibit the growth of the recipient strain.

Answer 1

Centrifuging the donor strain and resuspending it in fresh medium is essential to remove any antibiotics or growth-inhibiting byproducts (like acid or alcohol) that could affect the recipient strain, thereby allowing for a successful transfer of genetic material without inhibited growth.

Step-by-step explanation:

It is crucial to centrifuge the donor strain, discard the original media, and resuspend it in fresh Luria broth before mixing with the recipient strain to avoid inhibitory effects on the recipient. For instance, if the donor was grown in a medium with kanamycin, an antibiotic that the recipient might be sensitive to, the presence of kanamycin in the mix would inhibit the growth of the recipient.

Moreover, if the donor produces metabolic byproducts such as acids or alcohol through fermentation, these could lower the pH or generate toxic conditions, further inhibiting the recipient strain's growth. Therefore, the fresh medium ensures that the recipient cells are not exposed to any substances that could hinder their survival and growth, allowing for an accurate study of the transfer of genetic material without the interference of growth-inhibiting factors.